Dequard-Chablat M
J Biol Chem. 1986 Mar 25;261(9):4117-21.
In the fungus Podospora anserina, the su12-1 mutation was previously found to decrease translational accuracy and to alter the ribosomal protein S7. The mutant protein is more basic than the wild type. Among the revertants of the two ribosomal mutations su12-1 and su12-2, 29 contained a second mutation very closely linked to su12. Biochemical analysis of these revertants by functional poly(U) tests and electrophoretical study of the ribosomes led to two conclusions. First, some revertant strains contain new mutant forms of S7. This suggests that su12 is the structural gene for the ribosomal protein S7. Second, the su12-2 revertants display antisuppressor properties in vivo and in vitro (i.e. increased translational accuracy). The electrophoretical patterns of their ribosomal proteins show new, more acidic, forms of S7. Therefore, su12 can be mutated towards either a lower or a greater translational accuracy corresponding to two opposite modifications of the global charge of the ribosomal protein S7. A more acidic form than wild type leads to increased accuracy and a more basic form to decreased accuracy.
在真菌嗜热栖热放线菌中，先前发现su12 - 1突变会降低翻译准确性并改变核糖体蛋白S7。突变蛋白比野生型更具碱性。在两个核糖体突变体su12 - 1和su12 - 2的回复突变体中，29个含有与su12紧密连锁的第二个突变。通过功能性聚（U）测试对这些回复突变体进行生化分析以及对核糖体进行电泳研究得出了两个结论。首先，一些回复突变菌株含有新的S7突变形式。这表明su12是核糖体蛋白S7的结构基因。其次，su12 - 2回复突变体在体内和体外均表现出反抑制特性（即提高了翻译准确性）。它们核糖体蛋白的电泳图谱显示出S7的新的、更具酸性的形式。因此，su12可以朝着较低或较高的翻译准确性发生突变，这分别对应于核糖体蛋白S7整体电荷的两种相反修饰。比野生型更具酸性的形式会导致准确性提高，而更具碱性的形式则会导致准确性降低。
